feat(tools): add send_file tool for cross-platform file sharing

- Add new send_file tool to send audio, image, video, document files
- Support Feishu, Telegram, Discord, Slack, WhatsApp, Signal, Email, etc.
- Enhance Feishu adapter: auto-detect open_id vs chat_id, upload audio files
- Support home channel fallback when no explicit chat_id provided
- Add caption support for file messages

Related tests pass (104 passed, 11 skipped)

toolsets.py

@@ -57,7 +57,7 @@ _HERMES_CORE_TOOLS = [
     # Cronjob management
     "cronjob",
     # Cross-platform messaging (gated on gateway running via check_fn)
-    "send_message",
+    "send_message", "send_file",
     # Home Assistant smart home control (gated on HASS_TOKEN via check_fn)
     "ha_list_entities", "ha_get_state", "ha_list_services", "ha_call_service",
 ]
@@ -128,7 +128,7 @@ TOOLSETS = {
     
     "messaging": {
         "description": "Cross-platform messaging: send messages to Telegram, Discord, Slack, SMS, etc.",
-        "tools": ["send_message"],
+        "tools": ["send_message", "send_file"],
         "includes": []
     },